Honestly, most non tube AMPS sound the same, let alone DACs. But then you would have to admit that most adults can only hear up to 16kHz, most of the music content you listen to is in the under 10kHz range, SINAD is way past human hearing, vinyl is often transcribed from digital recordings, microphones are often digital these days so no analog version of sound even exists, and a myriad of other uncomfortable truths that audiophiles don’t like.

Burn in is such a dubious concept that you should probably just listen to music and see if you like them. If burn in exists at all, the changes would likely be extraordinarily small and well beyond human perception.

Cough cough. You don’t need a dac any more and only need an amp if your headphones are harder to drive. Cough* internal DACs have become much better in the last 3 decades* cough.